Optical signals are used in such fields as communication, robotics, medical imaging, and navigational systems. For example, optical coherence tomography (OCT) involves imaging human tissue using optical fibers to carry the image signal. In OCT, an imaging engine uses a fiber optic catheter to send light into a patient's body to collect an image.
Electrical motors move the catheter into place and rotate it at speeds well above 10,000 RPM to collect the image. The rotation and the imaging are coordinated by a microchip in the imaging engine. The optical signal is digitized while electrical signals control the motors.
Where optical and electrical signals are transmitted together, joints present problems. For example, where a downstream component must rotate relative to an upstream instrument, a motor must be provided along the signal line to drive the rotation. Not only does arranging the signal lines around the motor pose logistical problems, the rotation causes problematic vibrations. For example, some optical couplings go out of alignment when rotated at 5,000 RPM.
Further, existing optical couplings are typically not easy to connect and dis-connect. To service or replace one component of an optical system can require replacement of the entire system or significant system down-time. Even a routine event such as sterilizing an imaging catheter can require a medical imaging system to be taken out of service because the catheter is fixed to the imaging engine.